Burner for a Turbo Machine, Baffle plate for Such a Burner and a Turbo Machine Having Such a Burner

ABSTRACT

The invention relates to a burner for a turbomachine, comprising a guide plate that is arranged in a flame chamber and engages a wall section via spacers. The invention further relates to a guide plate, the fastening section of which comprises a plurality of raised areas for fastening to a wall section of a flame chamber. The invention further relates to a turbomachine having a burner of said kind.

PRIORITY CLAIM

This is a U.S. national stage of application No. PCT/EP2008/008936, filed on Oct. 22, 2008. Priority is claimed on the following application(s): Country: Germany, Application No.: 10 2007 050 664.5, Filed: Oct. 24, 2007 the content of which is incorporated here by reference.

FIELD OF THE INVENTION

The present invention relates to a burner for a turbo machine and more specifically to a burner having a baffle plate for guiding an air stream in a flame chamber.

BACKGROUND OF THE INVENTION

In a combustion process taking place in a flame chamber of a burner for turbo machines, radiant heat is formed, heating up in particular the chamber wall bordering the flame chamber. With thick walls and/or overlapping of material, this heating leads to high thermal stresses. The respective wall sections of the flame chamber are usually cooled by convection, in which outside air is guided over exterior surfaces of wall sections facing away from the flame chamber. To reduce the thermal stresses and to optimize convection cooling, the flame chambers are usually made of thin-walled sheet metal constructions such as flame tubes. Changes in cross section or measures to guide the flow of a mixed fuel-air stream or an air stream, such as baffle plates or swirl generators are welded in place. The baffle plates may be designed as conical rings having a mounting section for welding to a wall section of the flame chamber and having a flow guide edge facing away from the mounting section. After welding, the baffle plate with its mounting section is in contact with the wall section of the flame chamber over a large area, thus forming a large-area overlap of material, which promotes the development of thermal stresses. Since the overlap areas can be cooled on only one side, the thermal stresses cannot be adequately reduced.

SUMMARY OF THE INVENTION

It is an object of the present invention is to minimize the thermal stress associated with a burner for turbo machines while retaining the proven boundary conditions with regard to fluid mechanics and to create a turbo machine having such a burner.

An inventive burner for a turbo machine has a flame chamber, a swirl generator for applying a swirl to an air stream and a baffle plate arranged in the flame chamber for flow guidance of the air stream in the flame chamber. The baffle plate has a mounting section for mounting on a wall section of the flame chamber. According to the invention, the mounting section is connected to the wall section of the flame chamber by a plurality of spacers. The connection may traditionally be achieved by welding. The spacers first prevent an overlapping of material over a large area between the mounting section and the baffle plate and the wall section of the flame chamber. Secondly, a substream of air may flow between the mounting section of the baffle plate and the wall section of the flame chamber, resulting in cooling of both sides of these wall sections. In other words, the wall sections are cooled according to the invention on the interior surface facing the flame chamber as well as traditionally on their exterior surface facing away from the flame chamber. Likewise, welded joints for mounting the baffle plate are cooled on both sides.

The spacers may be separate components or may be, for example, elevations on the mounting section or on the wall section of the flame chamber, which are achieved by a corrugated shaping of the mounting section and/or the wall section.

The inventive baffle plate for a burner of a turbo machine has a flow guidance edge for guiding an air stream and a mounting section facing away from the flow guidance edge for mounting the baffle plate to a wall section of the burner. According to the invention, the mounting section has a plurality of elevations by which it can be attached to a wall section of a flame chamber of a burner.

In a preferred exemplary embodiment, the elevations each extend from a mounting edge of the mounting section to the flow guidance edge. This forms a plurality of channels between the elevations, extending essentially in the flow direction of the air stream. This has the advantage that a substream of the injected air can flow between the mounting section of the baffle plate and the wall section of the flame chamber virtually without any change in direction.

The elevations preferably taper out in the direction of the flow guidance edge and develop into a planar flow guidance section. Retaining the planar flow guidance section with its linear flow guidance edge has the advantage that the proven flow-optimized boundary conditions remain unchanged.

The elevations may be designed like corrugations having a plurality of wave crests and wave troughs. The wave troughs serve as the channels for air guidance for convection cooling between the mounting section of the baffle plate and the wall section of the flame chamber.

In one exemplary embodiment, the elevations are designed like steps in the form of a square-wave curve.

The wave crests and wave troughs preferably each have a uniform geometry and are uniformly arranged on the mounting section. This allows uniform cooling to be achieved over the circumference of the baffle plate.

In a preferred exemplary embodiment, the baffle plate is a conical baffle plate ring made of a trapezoidal strip of material having one short longitudinal side and one long longitudinal side. The flow guidance edge here is arranged on the short longitudinal side and the mounting edge is arranged on the long longitudinal side.

An inventive turbo machine has a burner with a baffle plate, which is spaced a distance away from wall sections of a flame chamber by means of spacers in some areas.

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred exemplary embodiments of the present invention are described in greater below on the basis of the drawings, in which

FIG. 1 shows a greatly simplified partial longitudinal cross-sectional view through a flame chamber of burner of the present invention;

FIG. 2 shows a first embodiment of a baffle plate of the present invention;

FIG. 3 shows a second embodiment of a baffle plate of the present invention;

FIG. 4 shows a third embodiment of a baffle plate of the present invention; and

FIG. 5 shows a fourth embodiment of a baffle plate of the present invention.

DETAILED DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENTS

FIG. 1 shows a partial longitudinal sectional view through the burner 2 for a turbo machine in the area of its fuel and air injection. The burner 2 is embodied in a welded sheet metal design and has a flame chamber 4 bordered axially by a circular burner plate 6. Nozzles (not shown) are arranged in the burner plate 6 to inject a fuel 8 into the flame chamber 4. The flame chamber 4 opens conically starting from the burner plate 6 and is bordered essentially by a flame tube 10 radially.

A swirl generator 12 is provided between the burner plate 6 and the flame tube 10 for injecting air 14 and for applying a swirl to same. The swirl generator 12 extends around the flame chamber 4 radially and is oriented axially with the longitudinal axis 16 of the burner 2. Because of the conical design of the flame chamber 4, the swirl generator 12 has an obliquely inclined inlet opening 18 for the air 14 into the flame chamber 4. A curved edge section 20 of the swirl generator 12 bordering the inlet opening 18 and located a distance away from the burner plate 6 is connected with a butt joint to a conical wall section 22 of the flame chamber 4.

The flame tube 10 is connected to the wall section 22 with a stepped end section 24, such that an annular space 20 is formed between an edge area 26 of the wall section 22 spaced a distance away from the swirl generator 12 and the stepped end section 24 of the flame tube 10.

The baffle plate 30 of the present invention, which is shaped to form a baffle plate ring, is situated in the connecting area of the swirl generator 12 to the wall section 22. The baffle plate ring 30 is designed with a conical shape and has a mounting section 32 and a flow guidance edge 34 facing away from the mounting section 32. The baffle plate ring 30 is arranged on an interior surface 36 of the wall section 22 via a mounting section 32, which is illustrated in greater detail in FIG. 2, such that the flow guidance edge 34 protrudes into the inlet opening 18 over the edge section 20 of the swirl generator 12. A plurality of channels (not shown) are formed between the wall section 22 and the mounting section 32 of the baffle plate ring 30 because of inventive elevations 48 of the mounting section 22 shown in the following FIGS. 2 through 5. During operation of the burner 2, a substream of the air 14 injected through the inlet opening 18 of the swirl generator 12 flows through these channels, thereby cooling by convection the interior surface 36 of the wall section 22 section by section and thus reducing thermal stresses in the baffle plate ring 30 and the wall section 22. Likewise, the mounting section 32 of the baffle plate 30 is cooled by the substream of air 14. Flow of the substream of air 14 into and through the channels is facilitated by a drop in pressure which is established in the channels.

According to FIG. 2, the conical sheet metal ring 30 is formed by a trapezoidal material strip 38. The material strip 38 has one short longitudinal side 40 and one long longitudinal side 42 opposite it. The two longitudinal sides 40, 42 are connected to one another by two narrow sides 44, 46 facing away from one another. The narrow sides 44, 46 are brought into connection for a butt joint to form the sheet metal ring 30.

The short longitudinal side 40 has the flow guidance edge 34, which is designed to be straight in the unshaped state of the material strip 38 according to the diagram in FIG. 2.

The mounting section 32 extends from the long longitudinal side 36 in the direction of the flow guidance edge 34. It has a plurality of elevations 48, which are corrugated in shape, thus forming a plurality of wave crests 50 a, 50 b, 50 c, . . . and wave troughs 52 a, 52 b, 53 c, . . . . When mounted in the flame chamber 4, the sheet metal ring 30 is attached to the interior surface 36 of the wall section 22 via the wave crests 50 a, 50 b, 50 c, . . . in at least some sections. The mounting is preferably accomplished by means of known welding techniques such as spot welding. The elevations 48 and/or the wave crests 50 a, 50 b, 50 c, . . . thus function as spacers by means of which the mounting section 32 is spaced away from the wall section 22, so that overlapping of the material over an area is prevented. The wave crests 52 a, 52 b, 52 c, . . . here serve as the above-mentioned channels in FIG. 1 through which the substream of air 14 flows for convection cooling of both sides of wall section 22. Likewise, the welded joints for mounting the sheet metal ring 32 are also cooled by the inventive convection cooling taking place in the interior of the flame chamber 4 in the mounting area of the sheet metal ring 30.

The elevations 48 extend from a mounting edge 54 formed by the long longitudinal side 42 in the direction of the flow guidance edge 34 and develop into a plane or flow guidance section 56 which is adjacent to the mounting section 32. The wave crests 50 a, 50 b, 50 c, . . . run radially outward in the direction of flow through this extent. The wave crests 50 a, 50 b, 50 c, . . . and the wave troughs 52 a, 52 b, 52 c, . . . each have the same geometry and are distributed uniformly over the mounting section 32 so that they run symmetrically on both sides of the mounting section 32.

The wave form of the mounting section 32 is responsible for a certain elasticity of the baffle plate ring 30, so that in addition to improved cooling, the thermal stresses are better compensated and/or minimized. The uniformity of the wave form described above results in the thermal stresses being uniformly dissipated over the circumference of the baffle plate 30 and no new stresses being introduced into the baffle plate ring 30.

FIGS. 3, 4 and 5 each show another embodiment of a baffle plate 58, 60, 62 of the present invention. The essential difference between these baffle plates 58, 60, 62 and the baffle plate 30 illustrated in FIG. 2 consists of the fact that the number of elevations 48 and thus the frequency of the wave form of the mounting section 32 are higher in FIG. 2 through FIG. 5. A detailed description of baffle plates 58, 60, 62 shown in FIGS. 3, 4 and 5 may thus be omitted.

It should be pointed out that it is also conceivable for the elevations 48 to be arranged on the mounting section 32 with different geometries and/or uniformly around the circumference of the baffle plate ring 30, in such a way that the convection cooling is executed with differing intensities over the circumference of the wall section 22. A stepped design in the form of a square-wave curve or a sawtooth curve can be mentioned as an example of a different geometric arrangement. In addition, it is conceivable for the channels to widen in a funnel shape in the direction of the mounting edge, so that an intensified nozzle effect occurs for continuous flow of the substream of air 14 in the channels. It is likewise conceivable for the elevations to be designed on wall section 22 and for the mounting section 32 of the baffle plate ring 30 to be planar. Furthermore it is conceivable for the elevations 48 to be replaced by external spacers or those designed separately, arranged between the wall section 22 and a mounting section. Furthermore it should be pointed out that any shapes of a baffle plate 30 are suitable, and the present invention is not limited to a ring shape.

A burner for a turbo machine having a baffle plate arranged in a flame chamber is disclosed, said baffle plate acting on a wall section via a spacer, a baffle plate whose mounting section comprises a plurality of elevations for attachment to a wall section of a flame chamber as well as a turbo machine having such a burner.

The invention is not limited by the embodiments described above which are presented as examples only but can be modified in various ways within the scope of protection defined by the appended patent claims. 

1-11. (canceled)
 12. A burner for a turbo machine comprising a flame chamber (4) including a wall section; a swirl generator (12) for applying a swirl to an air stream; a baffle plate (30; 58; 60; 62) for guidance of the air stream in said flame chamber (4); said baffle plate (30, 58, 60) comprising a mounting section; and a plurality of spacers for mounting said baffle plate with said mounting section on said wall section of said flame chamber.
 13. The burner according to claim 12, wherein said spacers comprise one of elevations (48) in said mounting section (32) of said baffle plate (30; 58; 60; 62) and elevations in said wall section (22) of said flame chamber (4).
 14. The burner according to claim 12, wherein said baffle plate further comprises a flow guidance edge (34) for guiding of an air stream, said mounting section (32) facing away from said flow guidance edge (34) for mounting the baffle plate (30; 58; 60; 62) on said wall section (22) of said flame chamber (4) of said burner (2); and said spacers being formed by a plurality of elevations (48) at said mounting section (32).
 15. The burner according to claim 14, wherein said baffle further comprises a mounting edge (54) and said elevations (48) extend from said mounting edge (54) in said direction of said flow guidance edge (34).
 16. The burner according to claim 15, wherein said baffle further comprises a planar flow guidance section (56) and wherein said elevations (48) taper out in the direction of said flow guidance edge (34) and develop into said planar flow guidance section (56).
 17. The burner according to claim 14, wherein said elevations (48) are formed as corrugations having wave crests (50 a, 50 b, 50 c, . . . ) and wave troughs (52 a, 52 b, 53 c, . . . ).
 18. The burner according to claim 17, wherein said wave crests (50 a, 50 b, 50 c, . . . ) and wave troughs (52 a, 52 b, 52 c, . . . ) each have a uniform geometry and are arranged uniformly on said mounting section (32).
 19. The burner according to claim 16, wherein said elevations (48) are constructed as steps in the form of a square-wave curve.
 20. The burner according to claim 15, wherein said baffle plate (30; 58; 60; 62) is a trapezoidal material strip (38) having one short longitudinal side (40) and one long longitudinal side (42) which forms a conical baffle plate ring in said deformed state.
 21. The burner according to claim 20, wherein said flow guidance edge (34) is arranged on said short longitudinal side (40), and said mounting edge (54) is arranged on said long longitudinal side (42).
 22. A turbo machine comprising a burner according to claim
 12. 